Barite

COLOR

Grey. Takes a rather good polish. No pleochroism.

REFLECTANCE

Very low. Strongly higher than quartz.

ANISOTROPISM

Not visible. Very abundant white or yellowish internal reflections.

TEXTURE

The mineral shows numerous cleavages. Thus triangular pits are quite common. Barite shows a strong tendency to develop idiomorphically and occurs as lamellae which are often radiating.

ASSOCIATED MINERALS

Galena, sphalerite, pyrite, chalcopyrite, bournonite, linneite, bravoite, silver minerals, quartz, fluorite.

CRITERIA OF DETERMINATION

The lamellar texture, triangular pits, reflectance slightly higher than quartz are characteristic. Also the softness which can be easily determined by scratching the polished section.

Source

ATLAS OF ORE MINERALS (P. Picot and Z. Johan)